Earlier quoted context omitted.
The existence of specialty sets doesn’t subtract from creating building. My kids get some of the specialty sets, build them, then hours later they’re either taken apart or heavily modified. The specialty sets can provide some interesting unique pieces too. My kids have a photographic memory of each of those special pieces and which set they came from. They’ll remember them and search until they find that exact piece.…
Off-topic, but: > My kids have a photographic memory How do you know it is photographic memory? More than one of your kids have it? Do you know why or what may have contributed to its development?
Read the whole sentence- this is clearly an informal use of 'photographic memory' to indicate that his kids are really into Lego and keep track of details in the way only kids can.